CHAPTER 6. LONG-TERM CONSEQUENCES
transport system of these
nerve cells. In conditions such
as Alzheimer’s and CTE, tau
instead forms tangles that
clump together to disrupt the
cells’ transport system. These
are known as neurofibrillary
tangles and sometimes
simply tau tangles. They’re
a cellular signpost of what
are known as tauopathies:
the group of degenerative
diseases associated with
aggregations of tau protein
in the brain. These tangles
are thought to eventually
lead to the death of neurons.
As more and more neurons
die and large areas of brain
tissue become affected,
symptoms such as those
described by Martland appear:
memory loss, confusion,
Parkinson’s-like tremors,
walking problems, impaired
judgement, depression
and personality changes.
CONCUSSION AND
OTHER DISORDERS
Evidence also suggests that
repeated concussion may
increase the risk of developing
other neurodegenerative
conditions such as Alzheimer’s
and Parkinson’s disease, as
well as conditions such as
depression. A study of more
than 2000 former American
footballers, for example, found
that players with a history
of multiple concussions
were three times more
likely to have been diagnosed
with clinical depression
than the general population.
A 2014 report from the
American National Football
Association predicted that
nearly 30 per cent of former
players may go on to develop
chronic brain conditions
as a result of trauma.
CTE RESEARCH BRINGS
MORE QUESTIONS
It’s only since the early
2000s that CTE has been
linked to concussion and,
not surprisingly, there
is still much work to be
done in understanding the
relationship between the
two. We are, however, only
W e now have a reasonable understanding of how
the accumulation of tau that can form tangles
damages neurons and causes the symptoms of
dementia. However, explains QBI’s Professor Jürgen Götz,
we have less of an understanding about what causes tau
to accumulate in the first place. One theory, he says, is
that tau is physically dislodged from its orderly structure
inside axons by the impact of a concussive head injury,
altering its conformation and localisation in a nerve cell.
3 PHASES OF ALZHEIMER'S DISEASE.
1. Healthy neuron. 2. Neuron with amyloid plaques (yellow).
3. Dead neuron being digested by microglia cells (red).
THE SOURCE OF TANGLED TAU
1
3
2